Speed regulated oil delivery system

ABSTRACT

An exemplary oil delivery system comprises a dual pump system configured for reducing the buildup of pressure by unloading one or both pumps, thus reducing the buildup of heat within the hydraulic system. The dual pump system is configured for delivering oil in combination to a single hydraulic system or to two completely separate hydraulic systems. In addition, the oil delivery system can also be configured to unload one or both of the pumping sections at a pre-determined speed to again limit the flow to any existing open centered hydraulic system. As a result, the oil delivery system recirculates oil back to the reservoir and/or the inlet to the pump in the absence of a buildup of pressure, and thus an absence in the buildup of heat to conserve energy.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is an application claiming priority from prior pending U.S. Provisional Application No. 60/192,997, filed on Mar. 28, 2000.

FIELD OF THE INVENTION

[0002] The present invention relates to an oil delivery system. More particularly, the present invention relates to speed regulated oil delivery system for use in mobile applications and the like, and which can provide, among other advantages, a reduced operating temperature, higher efficiency, reduced fuel consumption and an improved cycle time.

BACKGROUND OF THE INVENTION

[0003] In hydraulic systems, such as those used in various mobile applications, excessive pump flow can cause undesirable heat buildup that can result in damage to the hydraulic systems. This heat buildup problem is more prevalent for applications which include a variable speed input to the hydraulic pump, such as for open center-type hydraulic systems. For example, these variable speed pumps are typically sized to run at lower revolutions per minute (RPM), such as 700 RPM, but the hydraulic system must be able to operate with higher output flow during a higher RPM range, such as 2100 RPM. Accordingly, by forcing additional oil flow to the system at higher engine speeds, more pressure is required, which thus translates into additional heat buildup. Thus a need exists for determining how to limit the amount of oil flow during operation of the hydraulic systems, such as during higher speeds.

[0004] Historically, the most frequently used method to limit flow comprised the installation of a “dry valve” on the suction or inlet side of the hydraulic pump. The dry valve is configured to operate such that the valve can effectively cut off the inlet flow of oil to the pump, and thus allow only a very small amount of oil to be pushed by atmospheric pressure into the inlet of the pump at a very high vacuum. This small amount of oil is pushed through an orifice in the dry valve to lubricate the pump. Unfortunately, this dry valve operation starves the inlet of the pump, thus causing cavitation and eventual pump failure.

[0005] In addition, another detriment to using the prior art dry valve system is the susceptibility to failure of the dry valve. For example, on occasions when the control valve or dry valve sticks in an actuated position, when a control valve is shifted downstream, or when the small orifice of the dry valve becomes plugged, massive pump damage from cavitation or lack of lubrication most often results in the hydraulic system.

[0006] An example of the shortcomings of the prior art systems can be seen in hydraulic systems utilized in large refuse or garbage vehicles. For present refuse vehicle hydraulic systems, the slow speed of movement of the arm or other lifting mechanism is undesirable for most vehicle operators. Unfortunately as a result, instead of operating the engine in an “idle” status as designed, many operators frequently try to operate the equipment at an increased engine speed such as by shifting the engine to neutral. This increase engine speed operation tends to open the dry valve, and thus allows a full column of oil to go into the pump of the hydraulic system. To prevent this high speed operation, many hydraulic systems include a speed sensing control card for opening and closing the inlet side of the pump. However, many operators have since realized that the speed sensing card is integrated into the controls of the hydraulic system via an electrical connector which can be easily bypassed or “jumpered”, thus eliminating the speed control for the hydraulic system. As a result, due to the operators increasing of the engine speed, excessive pump flow is created that leads to heat buildup. Moreover, the excessive pump flow and increased speed causes the hydraulic and mechanical equipment to operate in an overspeed condition which results in premature wear and failure.

[0007] Accordingly, a need exists for an improved oil delivery system that addresses the problem of how to effectively limit or otherwise regulate the amount of oil flow within a hydraulic system to prevent heat buildup. In addition, a need exists for an improved oil delivery system with speed regulating features that addresses the problem of how to effectively limit or otherwise regulate the amount of oil flow to mechanical breakdown, such as that caused by operators increasing the pump flow of the hydraulic system in order to improve productivity of the equipment.

SUMMARY OF THE INVENTION

[0008] A speed regulated oil delivery system in accordance with the present invention addresses many of the shortcomings of the prior art. In accordance with one aspect of the present invention, an exemplary oil delivery system comprises a dual pump system configured for reducing the buildup of pressure by unloading the flow of oil from one or both pumps, thus reducing the buildup of heat within the hydraulic system. In accordance with an exemplary embodiment, the dual pump system comprises a first pumping section and a second pumping section, with each pumping section configured with an unloader valve.

[0009] In accordance with another aspect of the present invention, the oil delivery system can be configured to allow the combination of the flow of both pumping sections, at different flow rates and speeds, and unload one or both of the pumping sections at pre-determined speeds to again limit the flow to any existing open centered hydraulic system. As a result, the oil delivery system recirculates oil back to the reservoir and/or the inlet to the pumping sections without a buildup of pressure, and thus without the buildup of heat to enable the conservation of energy.

[0010] In accordance with another aspect of the present invention, the oil delivery system can also comprise a dual pump system configured for delivering oil to two completely separate hydraulic systems, with each pumping section configurable for different flow rates and speeds, and configured for unloading at similar or different pre-determined speeds.

[0011] In accordance with another aspect of the present invention, to provide for the loading and unloading of a dual pump system through the control of the unloader valves, the oil delivery system can suitably include a control mechanism which can comprise many forms and which is suitably configured for determining the engine or pump speed, and then providing a control signal to suitably load or unload at least one of valves

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in connection with the Figures, where like reference numbers refer to similar elements throughout the Figures, and:

[0013]FIG. 1 illustrates a schematic diagram of an exemplary oil delivery system in accordance with the present invention;

[0014]FIGS. 2A through 2C illustrate exemplary embodiments of an oil delivery system configured for operating a hydraulic system;

[0015]FIGS. 3A through 3C illustrate exemplary embodiments of an oil delivery system as may be utilized to operate two separate hydraulic systems; and

[0016]FIG. 4 is an exemplary embodiment of an unloader valve as may be configured with a pumping section.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

[0017] The present invention is described herein in terms of various hardware components and processing steps. It should be appreciated that such components may be realized by any number of hardware components configured to perform the specified functions. For example, in its various embodiments the present invention may include various hydraulic, pressure, and electronic components, e.g., pressure sensors, filters, valves, pumps, amplifiers, signal processing elements, solenoids, limit switches and the like, which may carry out a variety of functions either directly or under the control of one or more microprocessors, programmable logic controllers or other control devices. In addition, those skilled in the art will appreciate that the present invention may be practiced in any number of oil delivery contexts and that the illustrative embodiment described herein is merely one exemplary application for the invention. For example, in addition to the exemplary application with a hydraulic system for a refuse vehicle, the exemplary oil delivery system may be suitably implemented into hydraulic systems for other mechanically functioning, hydraulically operated equipment and the like. Further, it should be noted that the present invention may be suitably practiced within any variable speed, pressure or flow application, such as a variable speed engine, or a constant speed drive application with varying oil delivery requirements. Such general techniques that may be known to those skilled in the art are not described in detail herein.

[0018] As discussed above, excessive pump flow during operation of hydraulic systems causes several problems, including excessive heat buildup. This can be readily understood by using the well-known formula:

[(flow rate×pressure)/(1714×pump efficiency)]=input horsepower,

[0019] Accordingly, by reducing either the flow rate (GPM) or the pressure (PSI), the input horsepower can be reduced, which is directly proportional to the heat generated and the energy or fuel consumed.

[0020] In accordance with one aspect of the present invention, an exemplary oil delivery system comprises a dual pump system configured for reducing the buildup of pressure within the hydraulic system. In accordance with this aspect, the exemplary oil delivery system is configured for suitably addressing the pressure side or outlet of the dual pump system. For example, an exemplary oil delivery system may include one or more unloader valves, such as ventable relief valves or two-way valves, configured for unloading one or both pumps, thus reducing the buildup of heat within the hydraulic system.

[0021] In accordance with an exemplary embodiment, with reference to FIG. 1, an exemplary oil delivery system 100 suitably comprises a pair of control valves 118 and 120, a filter 116 and a reservoir 110. Control valves 118 and 120 are configured to facilitate operation of various cylinders or motors to permit operation of mechanical equipment, such as the raising and lowering of the arm of a refuse truck. In accordance with the exemplary embodiment, control valves 118 and 120 suitably comprise open centered directional control valves; however, control valves 118 and 120 can comprise any other type of control valve. Filter 116 suitably comprises any fluid conditioning mechanism, and can be configured for filtering, heating and/or cooling. In addition, filter 116 can be suitably configured with any type of drain or outlet for providing the fluid to reservoir tank 110. In the exemplary embodiment, filter 116 is configured as a return line filter. Meanwhile, reservoir 110 suitably comprises any reservoir or tank configured for containing fluid, providing cooling or other like functions, such as a vented or pressurized tank, with the fluid being received above or below the existing fluid level in tank. In accordance with an exemplary embodiment, reservoir 110 comprises a vented reservoir, with the oil return below the oil level.

[0022] To facilitate operation of control valves 118 and 120, oil delivery system 100 suitably includes a dual pump system 101 configured for delivering oil to two completely separate systems, such as to control valves 118 and 120. In addition, oil delivery system 100 may also include another fluid conditioning mechanism, such as a strainer 114 configured between dual pump system 101 and reservoir 110. Still further, oil delivery system 100 may also include a suction regeneration adapter configured for combining in a laminar like fashion the inlet of dual pump system 101 with any return flow lines, such as those described below. Regeneration adapter can comprise any configuration for facilitating the reinjection or recirculating of oil back into the inlet of dual pump system 101.

[0023] Dual pump system 101 suitably comprises a pair of pumping sections 102 and 104, with pumping section 102 configured for operation with control valve 118 and pumping section 104 configured for operation with control valve 120. Pumping sections 102 and 104 can comprise various pump configuration and types. For example, pumping sections 102 and 104 can be suitably configured in a double-vane type pump arrangement, or as gear pump or piston pump arrangements. In addition, pumping sections 102 and 104 can suitably comprise unidirectional or bidirectional type pumps, and fixed displacement or variable displacement type pumps. In accordance with the exemplary embodiment, for the purposes of illustration, pumping sections 102 and 104 suitably comprise a pair of fixed displacement, unidirectional pumps. However, it is to be understood that any pumping configuration can be utilized, and that these configurations will be referred to simply as “pumping sections.”

[0024] To facilitate the reduction in pressure buildup within oil delivery system 100, pumping sections 102 and 104 can be suitably configured with a pair of unloader valves 106 and 108 suitably coupled to the pressure side or outlet side of pumping sections 102 and 104. Unloader valves 106 and 108 can suitably comprise various types of relief valves or two-way valves, such as vented relief valves, proportional relief valves and the like. For example, unloader valves 106 and 108 can suitably comprise solenoid vented relief valves, solenoid operated two-way valves, electrically proportional relief valves, or electrically proportional two way valves.

[0025] Unloader valves 106 and 108 are suitably configured for permitting any oil discharged from the outlet of pumping sections 102 and 104 to flow either through open center valves 118 and 120 to the hydraulic cylinders and motors, or through valve 106 and 108 back to reservoir tank 110 or the inlet of pumping sections 102 and 104 at very low pressure. For example, unloader valve 106 can be suitably coupled between the outlet of pumping section 102 and the inlet of dual pump system 101, such as by way of a regeneration adapter, or by other suitable connection, while unloader valve 108 can be suitably coupled between the outlet of pumping section 104 and reservoir 110, such as by way of filter 116.

[0026] Accordingly, oil delivery system 100 can be configured to allow the flow of oil from one or both pumping sections 102 and 104, even at different flow rates and speeds, to the control valves 118 and 120, and then suitably unload one or both of pumping sections 102 and 104 to limit the flow. As a result, oil delivery system 100 can recirculate oil back to reservoir 110 and/or the inlet to pumping sections 102 and/or 104 without a buildup of pressure, and thus without the buildup of heat to enable the conservation of energy.

[0027] As discussed above, one detriment of using the prior art dry valve system is the high susceptibility to failure of the dry valves during operation. For example, on occasions when the control valve or dry valve sticks in an actuated position, when a control valve is shifted downstream, or when the small orifice of the dry valve becomes plugged, massive pump damage from cavitation or lack of lubrication most often results in the hydraulic system. However, through use of an exemplary dual pump system 101 within oil delivery system 100, if the control valves 118 and 120 were to stick or lose power, the oil would be suitably directed through valves 106 and/or 108 back to reservoir tank 110 or to the inlet of pumping sections 102 and/or 104, resulting in no damage to the oil delivery system 100, or the mobile equipment.

[0028] The above exemplary embodiments provide an oil delivery system 100 configured to allow the flow of oil from one or both pumping sections 102 and 104, even at different flow rates and speeds, to the control valves 118 and 120, and then suitably unload one or both of pumping sections 102 and 104 to limit the flow. In accordance with another aspect of the present invention, to determine when to suitably unload one or both of pumping sections 102 and 104, oil delivery system 100 can be configured to monitor, sense or otherwise observe the speed of operation of one or both of pumping sections 102 and 104; once the speed of operation for the pumping section being monitored reaches a threshold level of speed, oil delivery system 100 can utilize unloader valves 106 and 108 to unload the oil from one or both of pumping sections 102 and 104. In accordance with another exemplary embodiment of the present invention, oil delivery system 100 can also be configured to allow the combination of the flow of both pumping sections 102 and 104 and suitably unload one of the pumping sections at a predetermined speed to again limit the flow to any existing open centered hydraulic system.

[0029] For illustration purposes, with reference to FIGS. 2A through 2C, an exemplary oil delivery system 200 comprising a dual pump system 101 having, for example, equal sized pumping sections may be utilized in combination to supply oil to hydraulic systems 202 and 204, with each system 202 and 204 having an operational requirement of oil flow of 30 GPM at a speed of 725 RPM. In this example, the combined flow of dual pump system 101 is 30 GPM at a speed of 725 RPM, while at a higher speed of 1450 RPM, the combined flow increases to 60 GPM, i.e., with both valves 106 and 108 in a closed position as illustrated in FIG. 2A, the combined flow of dual pump system 101 can range between 30 GPM and 60 GPM at speeds between 725 RPM and 1450 RPM. Such a combination of flow from both pumping sections of dual pump system 101 may ideally be utilized at engine idle speeds, for example, at speeds between 600 RPM and 750 RPM, such as at 725 RPM.

[0030] If the control valves within hydraulic systems 202 and 204 are rated nominally at 40 GPM, it should be apparent that if the flow to the control valves is not limited, additional pressure will be needed to force the oil or other fluid through the valves, causing the development of additional heat and requiring significant additional fuel consumption. However, by unloading at least one of the sections of the dual pump system 101 at higher speeds, the total flow can be suitably limited to a level below the rating of the control valves. For example, with reference to FIG. 2B, if the speed of the dual pump systems exceeds the idle speed threshold of 725 RPM, oil delivery system 100 can limit the oil flow by unloading the oil flow through valve 106, i.e., the oil from pumping section 102. To prevent dual pump system 101 from “starving” for oil supply, unloader valve 106 can suitably unload the oil flow back to the inlet of dual pump system 101 to supplement the oil supply. The remaining oil flow can be provided from pumping section 104 to the hydraulic system. As a result, the total flow can be suitably limited to 30 GPM, which is safely below the 40 GPM rating of the control valves within hydraulic systems 202 and 204. Accordingly, by reducing the flow, the total horsepower can be suitably reduced, and thus the additional heat is not produced.

[0031] While FIG. 2B illustrates the opening of unloader valve 106 to permit the unloading of the oil flow to the inlet of dual pump system 101, it should be noted that oil delivery system 200 could also be suitably configured to only open unloader valve 108 such that oil flow could be directed to the reservoir tank 110. Furthermore, with reference to FIG. 2C, both pumping sections within dual pump system 101 can be unloaded if desired, such as by the opening of unloader valves 106 and 108 to permit the unloading of the oil flow to both the reservoir tank 110 and to the inlet of dual pump system 101, with no oil being provided to control valves of the hydraulic systems. For example, unloader valve 106 could be suitably opened at a low speed set-point or threshold, such as at 725 RPM, while unloader valve 108 could be suitably opened at a higher threshold, such as 1425 or 1800 RPM. As a result, both pumping sections of dual pump system 101 could be unloaded at low pressure.

[0032] In addition, while the above illustration depicts the unloading of oil flow through at least one of valves 106 and 108 to occur when the speed of pumping sections 102 or 104 reaches a low or high RPM, it should be noted that the unloading of oil flow could occur at various other low or high speeds, for example, at any speed greater than the lower RPM, e.g., any speed greater than 725 RPM, or any speed less than the maximum RPM, e.g., any speed less than 2100 RPM. In other words, the unloading of oil flow through at least one of valves 106 and 108 can be suitably configured to occur when the total oil flow is safely below, approximate to, or exceeding the nominal rating of the control valves.

[0033] To provide for the loading and unloading of dual pump system 101 through the control of valves 106 and 108, in accordance with another aspect of the present invention, oil delivery system 100 can suitably include a control mechanism which can comprise many forms, for example, automatic or manual operation, and electrical, mechanical, or electromechanical control. The control mechanism is suitably configured for determining the engine or pump speed, and then providing a control signal to suitably load or unload at least one of valves 106 and 108.

[0034] In accordance with an exemplary embodiment, oil delivery system 100 may comprise a control mechanism configured for electrical operation. In accordance with this embodiment, the electrically operated control mechanism can comprise a single input, dual adjustable output driver that is configured to sense the speed, e.g., the RPM, of the engine or pumping sections of dual pump system 101. Upon sensing the speeds, the output driver can suitably provide two separate outputs or other control signals to load or unload one or both sections of dual pump system 101. In other words, the electronic output driver can suitably determine the speed from the engines or pumps, and through control of the operation of valves 106 and 108, allow valves 106 and 108 to suitably open to permit oil flow to reservoir 110, to provide pressure and flow to the hydraulic systems, or to recirculate oil back to the inlet of dual pump system 101.

[0035] In accordance with an exemplary embodiment, the output driver card can suitably provide a separate output signal to each of unloader valves 106 and 108. For example, the output signal can comprise a power signal to actively open unloader valve 106 and a power signal to actively open unloader valve 108. In addition, the output driver card and unloader valves 106 and 108 could be configured such that a power signal from the output driver card closes unloader valves 106 and 108, and eliminating the power signal opens unloader valves 106 and 108. Such an arrangement could be very desirable if oil delivery system 101 loses system power, which would result in unloader valves 106 and 108 suitably opening to prevent or minimize any damage to the hydraulic system or the hydraulic cylinders and motors.

[0036] Moreover, the output driver card can be configured to unload dual pump system 101 at two or more different speeds, such as a at low speed of 700 RPM and at a high speed of 2000 RPM, or at various speeds in between. For example, the output driver card can be set to unload the first pumping section 102 at 1450 RPM, and to unload the second pumping section 104 at 1800 RPM. Thus for a hydraulic system that does not need to operate above 1800 RPM, pumping sections 102 and 104 can suitably unload and recirculate oil back to reservoir tank 110 or to the inlet of dual pump system 101 at a very low pressure.

[0037] In accordance with an exemplary embodiment, the electronic output driver can be configured on a control board or card for use with valves 106 and 108. In addition, the output driver card can be configured for adjustment, for example adjustment of the speed settings for loading and unloading, through hardware mechanisms to permit operator adjustment. However, to prevent equipment operators from readily adjusting the speed levels for activating the loading and unloading control signals, the adjustment of speed settings can be configured for software adjustment only. In addition, with reference to FIG. 4, the driver card and valves 106 and 108 can be suitably configured on the same device and mounted onto dual pump system 101, or the output driver and valves 106 and 108 can be separately mounted and connected.

[0038] Although the above exemplary embodiments disclose a dual pump system 101 configured to pump oil into a single hydraulic system to operate at a single speed, with reference to FIGS. 3A through 3C, oil delivery system 101 can also be configured for delivering oil to two completely separate systems 302 and 304. Moreover, when dual pump system 101 is configured for operating on two completely separate systems, it may be desirable for such a pumping configuration to be shut off at different engine or pump speeds. Accordingly, if desired, oil delivery system 101 could be configured to unload pumping section 102 at a first threshold speed, e.g., as illustrated in FIG. 3B, and to unload pumping section 104 at a second threshold speed, e.g., as illustrated in FIG. 3C, allowing the oil to be recirculated through the reservoir tank 110 and/or the inlet of pumping sections 102 and 104. Accordingly, since this recirculation of the oil through reservoir 110 does not require any additional pressure, no additional heat is produced, i.e., heat is dissipated, not generated, and fuel is conserved.

[0039] As a result, several major advantages of the speed regulated oil delivery system over the prior art can include a reduction in operating temperature, an increase in productivity and reliability, a higher efficiency and a reduction in fuel consumption, an decrease in cycle time, and a significantly quieter system overall. Still further, the oil delivery system can allow an operator to operate the hydraulic system and equipment “in gear” at engine idle speeds, and can allow the use of vane type pumps which are not readily compatible with prior art dry valve systems.

[0040] The present invention has been described above with reference to an exemplary embodiment. However, changes and modifications may be made to the exemplary embodiment without departing from the scope of the present invention. In addition, the various components of the oil delivery system may be implemented in alternate ways depending upon the particular application or in consideration of any number of design functions associated with the operation of the system. For example, although not described in detail above, the control device of the oil delivery system can be suitably driven by any device for providing an electrical control signal, such as a switch, PLC, microprocessor, pressure switch, limit switch, or other like means for supplying a controlled voltage or amperage to the control device. In addition, although only two pumps and control valves are shown and described above, an exemplary oil delivery system could be readily configured with any number of pumps and valves, all configured with a single or separate control device to operate and unload at any number of speeds or flow rates. In addition, although vented relief or two-way valves are shown above, the system can also be readily configured using soft shift, spool-type valves or electronically proportional relief valves to unload the pumps to the reservoir or the inlet to the pumps, thus eliminating decompression and the resulting pressure shock to the hydraulic system. These and other changes or modifications are intended to be included within the scope of the present invention. 

1. An oil delivery system configured to prevent heat buildup in a hydraulic system, said oil delivery system comprising: a reservoir tank for the storing of a hydraulic fluid; a dual pump system comprising a first pumping section and a second pumping section, each of said first pumping section and said second pumping section having an outlet configured for coupling to a control valve of the hydraulic system; a pair of unloader valves comprising a first valve and a second valve, said first valve being coupled between said outlet of said first pumping section and an inlet to said dual pump system, said second valve being coupled between said outlet of said second pumping section and said reservoir tank; and wherein said oil delivery system is configured to limit the amount of oil flow to the hydraulic system below a threshold level of oil flow by using speed regulation to determine when to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of unloader valves.
 2. The oil delivery system of claim 1, wherein said oil delivery system is configured to limit the amount of oil flow to the hydraulic system below a threshold level of oil flow by determining the speed of operation for at least one of said first pumping section and said second pumping section, and then recirculating the hydraulic fluid when a threshold level of speed has been obtained by said at least one of said first pumping section and said second pumping section.
 3. The oil delivery system of claim 2, wherein said oil delivery system is configured to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of unloader valves when a control valve of the hydraulic system becomes inoperable.
 4. The oil delivery system of claim 2, wherein said oil delivery system is configured to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of unloader valves when said threshold level of speed is greater than 725 RPM.
 5. The oil delivery system of claim 4, wherein said oil delivery system is configured to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of unloader valves when said threshold level of speed is greater than 1450 RPM.
 6. The oil delivery system of claim 2, wherein said oil delivery system is configured to recirculate the hydraulic fluid from both said first pumping section and said second pumping section.
 7. The oil delivery system of claim 6, wherein said oil delivery system is configured to recirculate the hydraulic fluid from said first pumping section at a first threshold level of speed and from said second pumping section at a second threshold level of speed.
 8. The oil delivery system of claim 7, wherein said oil delivery system is configured to recirculate the hydraulic fluid from said first pumping section at a speed of at least 700 PPM and from said second pumping section at a speed of at least 1400 PPM.
 9. The oil delivery system of claim 2, wherein said oil delivery system further comprises a control mechanism configured for sensing said speed of operation for at least one of said first pumping section and said second pumping section, and then providing at least one output control signal to said at least one of said pair of unloader valves to facilitate recirculation of the hydraulic fluid when a threshold level of speed has been obtained by said at least one of said first pumping section and said second pumping section.
 10. The oil delivery system of claim 9, wherein said control mechanism is configured to facilitate recirculation of the hydraulic fluid at different threshold levels of speed for said first pumping section and said second pumping section.
 11. The oil delivery system of claim 9, wherein said control mechanism comprises an electrically operated, single input, dual adjustable output driver card.
 12. The oil delivery system of claim 9, wherein said control mechanism is configured such that said threshold level of speed can only be adjusted through software adjustment.
 13. The oil delivery system of claim 2, wherein said dual pump system comprises a double-vane type pumping configuration.
 14. The oil delivery system of claim 2, wherein said dual pump system comprises a pair of fixed displacement, uni-directional type pumping configurations.
 15. The oil delivery system of claim 13, wherein said first pumping section and said second pumping section are configured to operate at different speeds at the same time and to provide oil flow to two separate hydraulic systems.
 16. The oil delivery system of claim 2, wherein said pair of unloader valves comprise at least one of a solenoid vented relief valve and an electrically proportional relief valve.
 17. The oil delivery system of claim 2, wherein said pair of unloader valves comprise at least one of a solenoid operated two-way valve and an electrically proportional two-way valve.
 18. A hydraulic system for providing hydraulic power for operation of mobile equipment, the hydraulic system comprising: a pair of control valves for providing directional control of oil flow to hydraulic cylinders used in the operation of the mobile equipment; a reservoir tank for the storing of hydraulic oil; a filter coupled between said pair of control valves and said reservoir tank, said filter configured for conditioning of the hydraulic oil; a dual pump system comprising a first pumping section and a second pumping section, each of said first pumping section and said second pumping section having an outlet configured for coupling to at least one of said pair of control valves; a pair of unloader valves comprising a first valve and a second valve, said first valve being coupled between said outlet of said first pumping section and an inlet to said dual pump system, said second valve being coupled between said outlet of said second pumping section and said reservoir tank; and a control mechanism for controlling operation of said pair of unloader valves; wherein said oil delivery system is configured to limit the amount of oil flow to the hydraulic system below a threshold level of oil flow by using speed regulation to determine when to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of unloader valves.
 19. The oil delivery system of claim 18, wherein said oil delivery system is configured to limit the amount of oil flow to the hydraulic system below a threshold level of oil flow by using said control mechanism for determining the speed of operation for at least one of said first pumping section and said second pumping section, and then recirculating the hydraulic fluid when a threshold level of speed has been obtained by said at least one of said first pumping section and said second pumping section.
 20. The oil delivery system of claim 19, wherein said oil delivery system is configured to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of valves when said threshold level of speed is greater than 1450 RPM.
 21. The oil delivery system of claim 20, wherein said oil delivery system is configured to recirculate the hydraulic fluid from both said first pumping section and said second pumping section.
 22. The hydraulic system of claim 21, wherein said oil delivery system is configured to recirculate the hydraulic fluid from said first pumping section at a first threshold level of speed and from said second pumping section at a second threshold level of speed.
 23. The hydraulic system of claim 19, wherein said control mechanism is configured for sensing said speed of operation for at least one of said first pumping section and said second pumping section, and then providing at least one output control signal to said at least one of said pair of unloader valves to facilitate recirculation of the hydraulic fluid when a threshold level of speed has been obtained by said at least one of said first pumping section and said second pumping section.
 24. The hydraulic system of claim 23, wherein said control mechanism is configured to facilitate recirculation of the hydraulic fluid at different threshold levels of speed for said first pumping section and said second pumping section.
 25. The hydraulic system of claim 19, wherein said first pumping section and said second pumping section are configured to operate at different speeds at the same time.
 26. A oil delivery system configured to minimize the overheating of a hydraulic system, said oil delivery system comprising: a reservoir tank for the storing of a hydraulic fluid; a dual pump system comprising a fixed-displacement type pumping configuration including a first pumping section and a second pumping section, each of said first pumping section and said second pumping section having an outlet configured for coupling to a control valve of the hydraulic system; a pair of unloader valves comprising a first unloader valve and a unloader second valve, said first unloader valve being coupled between said outlet of said first pumping section and an inlet to said dual pump system, said second unloader valve being coupled between said outlet of said second pumping section and said reservoir tank; and a control mechanism for controlling operation of said pair of unloader valves, said control mechanism being configured for sensing a speed of operation for at least one of said first pumping section and said second pumping section, and then for providing at least one output control signal to said at least one of said pair of unloader valves to facilitate recirculation of the hydraulic fluid when a threshold level of speed has been obtained by said at least one of said first pumping section and said second pumping section such that said oil delivery system is capable of limiting the amount of oil flow to the hydraulic system to minimizing the overheating of the hydraulic system.
 27. The oil delivery system of claim 26, wherein said oil delivery system is configured to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of unloader valves when a control valve of the hydraulic system becomes inoperable.
 28. The oil delivery system of claim 26, wherein said oil delivery system is configured to recirculate the hydraulic fluid from at least one of said first pumping section and said second pumping section through at least one of said pair of unloader valves when said threshold level of speed is greater than 1450 RPM.
 29. The oil delivery system of claim 26, wherein said oil delivery system is configured to recirculate the hydraulic fluid from both said first pumping section and said second pumping section, with the hydraulic fluid being recirculated from said first pumping section at a first threshold level of speed and from said second pumping section at a second threshold level of speed.
 30. The oil delivery system of claim 26, wherein said control mechanism is configured to facilitate recirculation of the hydraulic fluid at different threshold levels of speed for said first pumping section and said second pumping section.
 31. The oil delivery system of claim 30, wherein said control mechanism is configured such that said threshold level of speed can only be adjusted through software adjustment.
 32. The oil delivery system of claim 13, wherein said first pumping section and said second pumping section are configured to operate at different speeds at the same time. 